The present invention relates to installation and swaging tools and, more particularly, to a tool adapted to rotatably install a threaded insert to the correct depth and swage it in a workpiece in a single operation.
Oftentimes, it is necessary to install a fastener, such as an externally threaded bolt, in a workpiece that is made of aluminum or a composite material that is relatively soft by comparison to the material of the fastener However, installation of the fastener directly into the workpiece generally is not advisable, because the fastener is prone to being undesirably loosened or pulled out of the workpiece under the action of axial or perpendicular loads on the fastener. Under these circumstances, it is commonly known to install a steel insert or secondary fastener in the workpiece to receive the primary fastener Properly installed inserts are designed to securely hold the primary fastener in the workpiece under loads that would ordinarily cause the threads of the fastener to be stripped or pulled out of the softer parent material of the workpiece.
Inserts come in several different shapes and sizes, depending upon the nature of the work involved. One type of insert for which the installation tool of the present invention has application comprises a cylindrical body having an outer surface with external threads adapted for threaded reception within a threaded hole in the workpiece. The inner surface of the insert has internal threads adapted for threaded reception with the externally threaded primary fastener. To insure that the insert is securely connected to the workpiece, the insert has a plurality of serrations or barbs circumferentially arranged on the external surface of the insert at its outer end. After the insert is fully threaded into the workpiece hole to the correct depth, the barbs are swaged into a counterbore in the hole to securely connect the insert to the workpiece. In most workpieces, the steel barbs of the insert will be pressed into a positive mechanical engagement with the softer parent material of the workpiece so that both axial and rotational movement of the insert is restrained. Thus, when the primary fastener is installed, it is less likely to be pulled from the workpiece during normal use conditions.
Over the years, various installation procedures have been developed for installing inserts in workpieces. One known procedure involves a two-step operation in which a drive wrench having a hexagonally shaped key at its outer end engages a matching hexagonal wrenching surface on the threaded inner surface of the insert. The wrench has a handle that is rotated manually until the insert is threadably installed in the workpiece hole to the correct depth. In many instances, it takes several trials to accurately install the insert to the correct depth. Thereafter, the drive wrench is removed from the insert and a swaging tool is applied to the insert to manually swage the barbs radially outwardly into the counterbore of the workpiece hole.
The manual installation procedure described above, while effective, has several fundamental disadvantages. Most notable is that two separate installation steps involving two separate installation tools are required to install and swage the insert. This two-step procedure is relatively time consuming and requires careful attention and skill by the operator to insure that the insert is properly installed and swaged. Failure by the operator to fully thread the insert into the workpiece to the correct depth with the first tool could prevent the barbs from being properly swaged into the counterbore of the workpiece hole in the second step of the installation process. Similarly, even if the insert is fully threaded into the hole to the correct depth by the first tool, carelessness by the operator during the swaging operation with the second tool could result in a defectively swaged insert.
To avoid the problems inherent with the manual installation procedure described above, attempts have been made to produce a power tool for installing the inserts. However, none of the known power tools have been successful in installing and swaging the insert in a single operation.
Accordingly, there has existed a definite need for a power installation tool that will quickly and properly install and swage an insert in a workpiece in a single step, without requiring undue skill or attention by the operator. The present invention satisfies this need and provides further related advantages.